1. Technical Field
This disclosure relates to greenhouses and more particularly relates to air circulation systems inside of greenhouses.
2. Description of the Related Art
A greenhouse is a structure for growing plants. Typically, greenhouses are covered with various kinds of materials that allow the transfer of solar radiation to heat up the interior of the structure. These materials include glass or plastic or other transparent materials. Air warmed by the solar radiation is trapped in the building by the roof and walls of the structure, and may be absorbed by the plants and soil inside the structure.
The primary heating mechanism of a greenhouse is convection, or stated differently, the flow of air due to differences in temperature. Hotter air tends to accumulate near the ceiling of the greenhouse, and cooler air tends to accumulate near the floor of the greenhouse. Therefore, a common method for controlling temperature and preventing stagnant air inside of a greenhouse is to vent the greenhouse and allow hotter air to escape, for example, through a ventilation opening in the roof. However, in some climates it is not desirable to allow warm air to vent and therefore the result of prolonged periods of time without venting (i.e., during winter) is stagnant air that is not conducive to growing plants.